Electric and hybrid vehicles have recently become a more common sight on roads worldwide. They have one thing in common and that is they all require a large and powerful rechargeable battery. Despite the size of such batteries mounted in e.g. electric vehicles, they need to be recharged almost every day, depending on how frequently and how far the vehicle is driven.
The power required from a power source in order to recharge a rechargeable battery of an electric vehicle is substantial. This puts some requirements on the performance of cables and connectors of the entire charging system. A concern is the risk of e.g. a faulty connection, a broken cable or a loose connection which may be a hazard for a user. A faulty connection may cause an increase in electrical resistance between a power outlet and a cable connected between the power outlet and the battery. The increased electrical resistance causes an increase in temperature and the charging system may thus become a fire hazard.
For conventional charger systems there is commonly a dedicated cable with an integrated temperature sensor for detecting an increased temperature. However, such cables involve high complexity and are unnecessarily expensive.
WO2012107820 discloses a charging system capable of detecting a state of a connection of a charging cable for an electric or hybrid vehicle by measuring a voltage across reference resistors and comparing the measured voltage to a threshold voltage to determine a state of the connection. The charging cable of this system comprises a number of components required for analyzing the connection state of the cable to the vehicle. Although the disclosed system does not rely on a temperature measurement, it still requires a special and complicated cable. In particular, the system disclosed in WO2012107820 comprises a connection detection device included in the connector of the charging system.